<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>01-CSS入门</title>
    <style>
        #box1{
            width: 200px;
            height: 200px;
            background-color: red;
            border: 3px yellow solid;
        }
        .box{
            width: 300px;
            height: 300px;
            background-color: wheat;
            border: 3px black solid;
        }
    </style>
</head>
<body>
    <p id="box1">
        我是盒子1
    </p>
    <p class="box">
        我是盒子2
    </p>
</body>
</html>